1. Field of the Invention
The present invention relates mainly to a golf club and, more particularly, to those with shafts that have a specified cross-sectional shape.
2. Brief Description of the Prior Art.
So far golf clubs such as wood clubs have been accelerated in unweighting and in elongation in response to an enlargement in size of club heads. Recently, lightweight wood clubs with total weights between 290 and 300 grams have increased in number and ultra-lightweight clubs with total weights below 290 grams have appeared on the market.
If a golf club is lighter, one can swing the club faster to raise its head speed, assuming the length of the club is the same. Accordingly, the lightening and elongation of clubs have an advantage on the flying distance of a golf ball.
The aforementioned unweighting and elongation of the golf clubs are attained mainly by a progress in lightening the shafts and grips of the golf clubs.
However, as to the club shaft, its weight reduction has been realized by replacement of its constituting material with a lighter weight substance such as carbon fiber, while assuming the that cross-sectional shape of the shaft is a circle. So far, a substance lighter than carbon fiber has not appeared on the market. Consequently, weight reduction of the club based on changes in shaft material has a certain limitation.